The invention pertains to a system for manufacturing sheet-like printed products, e.g., pamphlet sheets, magazine sheets or invoice sheets, with a transport device that transports the starting material to be printed from a feed station through a printing station, in which at least one printed image is applied onto the starting material.
Systems of this type are, for example, used for manufacturing pamphlet sheets, magazine sheets, invoice sheets or similar sheet-like printed products which are printed on one or both sides and usually consist of paper material. In systems known so far, endless starting material that is wound into reels is processed. This starting material is continuously transported, among other things, through a printing station by means of a transport device that contains a series rollers or cylinders. The desired printed image is applied onto the web-shaped starting material in the printing station with the aid of a printing cylinder that adjoins the starting material. After the printing process, the printed starting material is cut to the desired format such that individual sheet-like printed products are ultimately obtained.
The disadvantages of these known systems are the relatively low processing speed and the lack of flexibility in applying the printed image. Consequently, the present invention is based on the objective of developing a system of the initially mentioned type which allows a very flexible manufacture of sheet-like printed products with high processing speed and high precision.
According to the invention, this objective is attained due to the fact that the feed station contains a transfer device for transferring starting material in the form of sheet-like starting sections to the transport device, the fact that the transport device is equipped with a vacuum conveyor belt, on which the sheet-like starting sections to be printed are held during their transport due to the vacuum, the fact that the printing station is equipped with a printer that operates in a contactless fashion and is preferably realized in the form of an ink jet printer as well as a dryer that is arranged behind the printer viewed in the transport direction of the starting sections, and the fact that an electronic printed image specification device that cooperates with the printer and makes it possible to specify individual printed images for the sheets is provided.
These measures result in a system in which endless starting material is not printed, but rather starting material in the form of formatted, sheet-like starting sections. The sheet-like starting sections are transported through the printing station with the aid of the vacuum conveyor belt, with the retention of the starting sections on the vacuum conveyor belt due to the vacuum allowing very high transport speeds without impairing the alignment of the starting sections. The processing of sheet-like starting sections provides the additional advantage that certain finishing treatments can be carried out before the starting sections are fed to the system, e.g., certain folds of the starting sections, without impairing the processing options in the system according to the invention. Due to the utilization of a printing station that is equipped with a contactless printer, the desired printed image can be easily varied without complicated resetting procedures, with a high precision always being ensured. The subsequently arranged dryer also ensures a reliable drying of the printed starting sections at high processing speeds, i.e., the printed image is fixed and can no longer smear. The electronic printed image specification device that is assigned to the printer makes it possible to manipulate the printing process during the operation of the system and, if so required, to assign individual printed images to the individual starting sections. Consequently, it is not only possible to manufacture printed products with the same printed image, but printed products with individualized printed images. For example, it is possible to manufacture personal invoice sheets or letters that are printed with specific contents for the respective recipient.
DE 9 111 877 U1 describes a system for printing flat objects which contains an ink jet printer that is coupled to a computer in such a way that the objects can be individually printed. However, the objects only lie loosely on a conveyor belt during their transport, i.e., the transport speed needs to be relatively slow in order to prevent the objects from changing their respective position. The lack of a dryer additionally reduces the processing speed. Although the drying time could be extended by lengthening the conveyor belt, this would result in a significant increase in the longitudinal dimensions of the system.
DE-OS 23 43 109 discloses a feed device for sheet-like objects which is equipped with a vacuum conveyor belt. EP 0 284 215 A1 describes a printer that is equipped with an infrared dryer. DE 195 27264 A1 describes a printing machine that contains several printing stations, between which devices for turning over the objects to be printed are arranged. DE 44 25 199 A1 discloses a printing device for printing web-like materials which contains several printing heads that are controlled by a control unit so as to variably manufacture different printed images.
Advantageous additional developments of the invention are disclosed in the subclaims.
If it is required to print a sheet-like starting section on both sides, the invention proposes to arrange a turning station between the printing station and an additional printing station of comparable design. In this case, one respective printing station that can be controlled by the electronic printed image specification device is provided for each side of the starting section to be printed.
In order to make it possible to process sheet-like starting sections that are delivered in the form of stacks, the transfer device assigned to the feed station is preferably provided with a decollating device that decollates the starting sections and deposits the decollated starting sections on the vacuum conveyor belt either individually or in groups of several successively arranged starting sections.
In order to achieve an exact positioning of the starting sections when they are deposited onto the continuously revolving vacuum conveyor belt, it is advantageous if the starting sections are deposited in a pre-accelerated fashion, preferably such that the transfer takes place at a transfer speed that corresponds to the conveyor belt speed and relative movements are prevented.
It has proved particularly practical to utilize a dryer that operates with infrared radiation and has a high drying efficiency, namely also at a very high transport speed of the printed starting sections and a correspondingly short dwell time of these starting sections within the region of the dryer.
Another advantage of the system can be seen in the fact that it can be operated with a continuous transport of the starting sections to be printed such that no down times which would decrease the throughput occur. A realistic transport speed would lie at 300 m/min. This would make it possible to print approximately 54000 sections per hour if sheet formats of conventional size are processed.
The system is preferably equipped with a delivery station, in which the printed and dried starting sections, i.e., the manufactured printed products, are received, so as to transport the printed products to additional processing stations if so required. The transport to additional processing stations can take place continuously, but it is also possible to stack the printed products until they are additionally transported.
The invention is described in greater detail below with reference to the enclosed figures.